84 SYSTEMATIC ARRANGEMENT 



creasing, with the nucleus very excentric. Shell oblong- turrited, 

 often truncated, sometimes globose-turbinated ; aperture ovate. 

 Peristome simple or more or less distinctly doubled, nearly straight, 

 expanded or broadly reflexed. 

 1. C. pictum, 



c. Pomatianina. Operculum thick,- of two horny coats, conca- 



merated within. 



27. POMATIAS. 



Operculum cartilaginous, few-whorled, composed of two plates, 

 concamerated within. Shell somewhat imperforate, conico-turrited 

 or turrited, longitudinally striated or ribbed. Peristome nearly sim- 

 ple or double, the internal edge continuous, the external expanded or 

 reflexed, often auriculated. 



I. P. maculata, t. 311. f. 19. 



d. Realiana. Operculum thin, horny ; front of last whorl with a 



keel round the axis, and sometimes a notch in the front of 

 the lip, like Pupiniana, but the operculum is ovate, few-whorled. 



28. Liarea. 



Operculum thin, few-whorled, horny. Shell turrited, rather 

 smooth ; aperture ovate. Peristome continuous, double. 



1. L. Egea. 



29. Realia. 



Operculum thin, few-whorled, horny. Shell perforate or narrowly 

 umbilicate, turrited, or globose-turbinate, keeled round the perfora- 

 tion ; aperture ovate. Peristome straight or expanded, with distant 

 margins. 



1. R. rubens, t. 311. f. 11. 



2. R. erosa, t. 311. f. 12. 



30. BOURCIERA. 



Operculum ovate, rather solid, horny, of a few rapidly-increasing 

 whorls. Shell Helicina-shaped ; columella toothed beneath ; aper- 

 ture ovate. Peristome spreading. 



1. B. helicinseformis. 



Fam. VII. OLIGYRADiE. 



Eyes on outer side of the base of the tentacles. -Gills vascular, 

 free. Shell conical or subglobose ; aperture half-ovate. Operculum 

 annular, not spiral, shelly, thick, or horny and thin, semi-ovate or 

 rather triangular ; nucleus subcentral, lateral. 



Terrestrial. 



The animal absorbs the septa between the upper whorls, as in 

 AuricuHdce, JlelicinidcP, Proserpina, Ncritina, &c. 



